Walking. We figure out how to do it after crawling for a while. We do it for decades without a second thought. We skip and run, we carry loads and climb ladders and live life on two feet. Walking is effortless.

When an injury happens, suddenly walking isn't so easy. We must learn how to walk again, step by wobbly step, using crutches, rails and the strong arm of a friend. Over the years our injuries accumulate. It isn't many few decades after we stop crawling that we begin to stiffen up and slow down. Arthritis brings persistent pain into our paces.

Healing is spontaneous most of the time, and sometimes we get knees repaired or joints replaced. When walking isn't so easy, we appreciate just how important it is. Our ability to walk is part and parcel with our lives.

Walking speed correlates directly with life expectancy in our later years. Fast walkers live longer. Overall, not in every specific case. When congestive heart failure (CHF) strikes and we are confined to our beds, walking can save us or kill us. Research has shown that most people with CHF get better when they begin a program of walking. A few individuals have worse outcomes, early, the rest of have better outcomes, period.